To study the role of interleukin-33 (IL-33) in acute exacerbation of allergic asthma induced by respiratory syncytial virus (RSV). Female BALB/c mice aged 3 weeks were randomly divided into five groups: PBS control; RSV infection; asthma mice model (sensitized and challenged by 1% ovalbumin); asthma model with RSV infection and treated with control antibody; asthma model with RSV infection and treated with anti-IL-33 antibody. Lung specimens were collected. The Lung sections were stained by hematoxylin-eosin to observe the changes of lung inflammation. il-13, il-4, rorγt, foxp3, ifnγ and il-33 mRNA expressions in the lung tissue were determined by real-time PCR. IL-13、IL-4、IL-33、IFN-γ and IL-17 level in bronchoalveolar lavage fluid(BALF) were measured by ELISA. Histological examination of lung tissue demonstrated that anti-IL-33 significantly inhibited allergen-induced lung inflammation. Both mRNA and protein level of IL-33 and IL-4 were significantly increased in the RSV asthma group. Treatment with anti-IL-33 significantly reduced the concentrations of IL-4, IL-13 and IL-17 compared with administration of a control antibody. The mRNA expression of il-13, il-4, rorγt, and foxp3 were also decreased. There was no change with IFN-γ expression. Our results demonstrated that anti-IL-33 antibodies can prevent the development of asthma in a mouse model, and blockade of IL-33 could be a new therapeutic strategy for acute exacerbation of allergic asthma.